Water pressure in a sportmaster at 60MPH

[Carter Powell]

What type of water pressure normally happens in a lower unit before it hits the water pump?

Thanks, Carter Powell

[KIRCHNER]

fresh water or salt?

[Carter Powell]

Fresh! Just trying to get an idea of the water pressure before it gets to the water pump.

thanks, Carter

[KIRCHNER]

im thinking no more than 30 lbs?

[gmorgan]

How and where are you gauging water pressure before the water pump?

[tlwjkw]

probably depends on whether ya hooked up to a garden hose or fire hydrant... sittin' still or runnin a hundred... never heard of anyone tryin' ta read "before" pump pressure..

[skialot2]

Probably not a lot. Otherwise, you would not overheat when going fast with a bad impeller. But you do.

[RBT]

Water psi is calculated as velocity squared times .0142
So, 60X60X.0142=51.12 psi

RT

[Carter Powell]

So I guess my original question should have been, how does this type of pressure effect the water pump impeller as the pressure rises? This is just something that I never thought about.

Many thanks, Carter

[Jim Speros]

It was an interesting question. Pitot pressure suggests there is for 70lbs at 70 mph and 144lbs at 100mph. That is not a flow thru situation. Cooling requires an abundant flow and relatively low pressure. High pressure in cooling suggests flow is hindered.

[hydra-sports]

the water pressure pre-impeller is irrelevent, it is basically a centrifical pump and works totally on suction

[Jim Speros]

Water pressure at 80mph and up is often higher with some gearcases. Over 100 mph over pressure can be an issue. AT those speeds the water pump is absolutely under pressure.